Leadless cardiac stimulation systems

Abstract

Various configurations of systems that employ leadless electrodes to provide pacing therapy are provided. In one example, a system that provides multiple sites for pacing of myocardium of a heart includes wireless pacing electrode assemblies that are implantable at sites proximate the myocardium using a percutaneous, transluminal, catheter delivery system. Also disclosed are various configurations of such systems, wireless electrode assemblies, and delivery catheters for delivering and implanting the electrode assemblies.

What is claimed: 
     
       1. A system, comprising:
 an elongate member; and 
 an intravascularly-deliverable leadless electrode assembly, comprising:
 a housing having a proximal end and a distal end, the housing defining an inwardly extending cavity that is located centrally on the proximal end of the housing and extends distally from a proximally facing cavity opening, the cavity providing access to an engaging feature, the engaging feature including a proximally facing side and a curved distally facing side having a predefined curved surface; 
 an attachment mechanism operatively coupled to the distal end of the housing and configured to secure at least a portion of the leadless electrode assembly to a myocardium of a heart, the attachment mechanism including a tip configured to penetrate into the myocardium of the heart; 
 an electrostimulation generator circuit situated in the housing; 
 respective electrostimulation electrodes coupled to the electrostimulation generator circuit and configured to provide an electrostimulation to the myocardium of the heart; and 
 
 wherein a portion of the elongate member is configured to extend through the proximally facing cavity opening into the cavity of the housing to access and releasably engage the curved distally facing side of the engaging feature in a non-threaded manner to control separation between the leadless electrode assembly and the elongate member when pulling on the elongated member in a proximal direction. 
 
     
     
       2. The system of  claim 1 , wherein the elongate member is configured to mechanically engage the curved distally facing side of the engaging feature using a user-applied pulling motion of the elongate member. 
     
     
       3. The system of  claim 2 , wherein the elongate member is configured to mechanically engage the curved distally facing side of the engaging feature using a combination of the user-applied pulling motion and a user-applied rotational motion of the elongate member. 
     
     
       4. The system of  claim 1 , wherein, when the portion of the elongate member is engaged with the curved distally facing side of the engaging feature, the elongate member and the leadless electrode assembly are sufficiently coupled to permit forcible removal of the attachment mechanism from the myocardium without disengaging the elongate member from the leadless electrode assembly. 
     
     
       5. The system of  claim 1 , wherein the attachment mechanism comprises one or more tines that have a retracted configuration and a user-extendable configuration, the one or more tines including respective tips configured to penetrate into the myocardium, and are configured to extend outward from the leadless electrode assembly, in the user-extendable configuration, in response to movement of the elongate member and the leadless electrode assembly relative to an intravascularly-deliverable delivery catheter by a user. 
     
     
       6. The system of  claim 5 , wherein the one or more tines are configured to transition from the retracted configuration to the user-extendable configuration in response to a user-applied linear motion of the elongate member and the leadless electrode assembly relative to the intravascularly-deliverable delivery catheter by the user. 
     
     
       7. The system of  claim 1 , wherein the attachment mechanism comprises a helical tine. 
     
     
       8. The system of  claim 1 , wherein the elongate member is configured to permit rotation of the leadless electrode assembly while the portion of the elongated member is engaged with the engaging feature. 
     
     
       9. The system of  claim 1 , further comprising:
 an intravascularly-deliverable catheter defining a lumen; 
 wherein the leadless electrode assembly and the elongate member are sized and shaped to transit the lumen of the intravascularly-deliverable catheter during delivery of the leadless electrode assembly to an implantation site or removal of the leadless electrode assembly from the implantation site. 
 
     
     
       10. The system of  claim 1 , wherein the leadless electrode assembly comprises a power source coupled to the electrostimulation generator circuit and configured to provide operating energy to the electrostimulation generator circuit. 
     
     
       11. The system of  claim 10 , wherein the power source includes a radioactive source. 
     
     
       12. An intravascularly-deliverable leadless electrostimulation electrode assembly, comprising:
 a housing having a proximal end and a distal end; 
 an attachment mechanism operatively coupled to the distal end of the housing and comprising a tine configured to secure at least a portion of the leadless electrode assembly to a myocardium of a heart, the tine including a tip configured to penetrate into the myocardium of the heart; 
 an electrostimulation generator circuit situated in the housing; 
 respective electrostimulation electrodes coupled to the electrostimulation generator circuit and configured to provide an electrostimulation to the myocardium of the heart; 
 wherein the proximal end of the housing defines a recess, the recess defined by sidewalls, an end wall, and is accessible by a recess opening at a single end of the recess, opposite the end wall, the recess opening facing in the proximal direction of the housing, the recess providing access to an engaging feature, wherein the engaging feature includes a proximally facing side and a distally facing side; and 
 wherein the recess is configured to receive at least a portion of an intravascularly-deliverable elongate member via the proximally facing recess opening and wherein the elongate member is changeable from a first configuration to a second configuration, wherein:
 in the first configuration, the elongate member engages in a non-threaded manner the distally facing side of the engaging feature in order to control separation of the leadless electrostimulation electrode assembly from the elongate member when pulling on the elongated member in a proximal direction; and 
 in the second configuration, the elongate member disengages from the distally facing side of the engaging feature and selectively detaches from the leadless electrostimulation electrode assembly. 
 
 
     
     
       13. The intravascularly-deliverable leadless electrode assembly of  claim 12 , wherein the elongate member includes one or more fingers, and wherein the distally facing side of the engaging feature is configured to be engaged by one or more of the fingers of the elongate member. 
     
     
       14. The intravascularly-deliverable leadless electrode assembly of  claim 12 , wherein the attachment mechanism comprises one or more tines that have a retracted configuration and a user-extendable configuration, the one or more tines including respective tips configured to penetrate into the myocardium, and are configured to extend outward from the leadless electrode assembly, in the user-extendable configuration, in response to movement of the elongate member and the leadless electrode assembly relative to an intravascularly-deliverable delivery catheter by a user. 
     
     
       15. The intravascularly-deliverable leadless electrode assembly of  claim 12 , comprising a power source coupled to the electrostimulation generator circuit and configured to provide operating energy to the electrostimulation generator circuit at least in part using a radioactive source. 
     
     
       16. A system, comprising:
 an intravascularly-deliverable elongate member; 
 an intravascularly-deliverable leadless electrode assembly, comprising:
 a housing having a proximal end, a distal end, and a cavity defined by a wall of the housing, the cavity disposed centrally within the proximal end of the housing, an interior of the cavity shaped to define an engaging feature, the engaging feature including a proximally facing side and a distally facing side, the distally facing side having a tangent that is perpendicular to a longitudinal axis of the housing; 
 an attachment mechanism extending out from the distal end, the attachment mechanism configured to secure at least a portion of the leadless electrode assembly to a myocardium of a heart;
 an electrostimulation generator circuit disposed in the housing; 
 
 respective electrostimulation electrodes coupled to the electrostimulation generator circuit and configured to provide an electrostimulation to the myocardium of the heart; and 
 a power source coupled to the electrostimulation generator circuit and configured to provide operating energy to the electrostimulation generator circuit; and 
 an intravascularly-deliverable catheter defining a lumen; 
 
 wherein the leadless electrode assembly and the elongate member are sized and shaped to transit the lumen of the intravascularly-deliverable catheter during delivery of the leadless electrode assembly to an implantation site or removal of the leadless electrode assembly from the implantation site; and 
 wherein the elongate member is configured to be received at least partially within the cavity of the leadless electrode assembly and to engage the distally facing side of the engaging feature in a non-threaded manner to control the separation between the elongate member and the leadless electrode assembly, the engaging feature and the elongate member are configured to selectively release the elongated member from the leadless electrode assembly.